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View Full Version here: : NGC 3324 Gabriela Mistral Nebula Visual Spectrum Synthetic LRGB from SHO Data Set


Startrek
09-02-2025, 10:37 PM
Due to imaging under Bortle 8 light polluted skies and with clear nights during a new moon period quite rare , I use a niche process in Startools via its Compose Module to create visual spectrum synthetic LRGB image from my acquired SHO narrowband Data set.
Here’s my recent version of NGC 3324 Gabriela Mistral Nebula in VS Synthetic LRGB.
It’s not bonafide LRGB but at least it’s another option to use with Narrowband data to create something close to the visual spectrum.
Using the ST Compose Module …..,
I create a synthetic Luminance channel from the individual SHO data sets
Then create the Red channel from Ha + Sii ( luminance color set to Mono )
The Oiii data is used for the Green channel ( luminance color set to Mono )
The Oiii data is also used for the Blue channel ( luminance color set to Mono )
Once composited , luminance color set to L, RGB

It’s great having another useful option in your processing.

Astrobin link below for full resolution……,
https://www.astrobin.com/9oyaz9/

Attached native and crop versions in 200KB

Thanks for Looking
Comments welcome

Martin

Startrek
11-02-2025, 09:32 PM
After going over this image a few times I wasn’t quite happy with the colour and saturation levels so decided to do a repro …..,
Adjusted Green and Blue bias
Reduced total saturation by 10%
Used the Entropy module to highlight contrast and brightness along the outer structures
I think the revised image has exposed a bit more fine detail and colour balance.

Astrobin link for full resolution…..,

https://cdn.astrobin.com/thumbs/s7lhdKlm74Vp_2560x0_esdlMP5Y.jpg

https://cdn.astrobin.com/thumbs/fPLmMncw9z1V_2560x0_esdlMP5Y.jpg

Thanks for Looking

Comments welcome

Martin

Dave882
11-02-2025, 11:03 PM
Martin I think that’s a big improvement to my eye. Colour looks a bit more natural and the detail a bit clearer too. In many ways I think I even prefer that to the sho version. Well done!

Ryderscope
12-02-2025, 08:16 AM
A clever way Martin to recompile your narrowband data using a different palette variation. Makes for a fine rendition for the final version.

Startrek
12-02-2025, 07:36 PM
Thanks Dave,
Yes definitely an improvement !
Although I should have worked on the stars to align them a bit closer to RGB. I still like the HST SHO version with those stereotypical golden and blue hues and I think the star colours are better in that image.
By the way I couldn’t find Gabby data from 2024 , might have deleted it or put it somewhere on a remote storage down the coast.

Martin

Startrek
12-02-2025, 07:42 PM
Thanks Rodney
Ivo , the inventor and developer of Startools gave me the procedure a couple of years ago.
Works great on most emission nebula because as your aware imaging broadband targets under Bortle 8 is really difficult and need mother nature to co operate during new moon over many many nights.

Cheers
Martin